Various types of range hoods have been proposed. The basic constitution in the range hoods is as described below. That is, an evacuating fan, which is incorporated in a hood main body, draws air or emitted gas, which contains oily smoke or vapor generated by cooking, and the air or emitted gas is evacuated to the outside of a house through an evacuating duct. Here, it is arranged so that the hood, which is largely opened downward over the kitchen range, traps the emitted gas.
In these days, so to speak “electromagnetic cooking appliances”, which employ the electricity, have been evolved and are as widely used as kitchen ranges that burn a gas to obtain source of heat necessary for cooking. In these electromagnetic cooking appliances, emitted gas, which contains carbon dioxide gas, is not generated. However, cooking generates vapor, which contains oily smoke and smell. It is needless to say that such oily smoke and the like has to be evacuated to the outside of a house.
Also, such electromagnetic cooking appliances as described above do not burn a gas. Therefore, the combustion air the gas is not required. However, satisfactory ascending air current like emitted gas, which is generated by burnt gas, cannot be formed. That is, when an electromagnetic cooking appliance is used, all of the oily smoke and vapor, which are generated by cooking, do not reach to the range hood, and in many cases, some part of them spreads in a kitchen. Particularly, for the range hood, it is preferred to provide a height of 80 cm or more from a pan or frying pan to the range hood. Accordingly, the spreading of the air containing such oily smoke and the like outside the range hood; i.e., the spreading in the kitchen is unavoidable.
Needless to say, in a range hood, which has the basic constitution as described above, the structure of the evacuating fan is important. That is, a silent evacuating fan having a strong evacuating power is required. The applicant of the present invention has proposed a technique concerning an evacuating fan, which is suitable to apply to such range hood, in Japanese Patent No. 260928 and the like. Also, the applicant has disclosed various techniques concerning the relevant hoods in the Japanese Patent No. 2920494, No. 2920494 and No. 3277250.
Owing to these techniques of the applicant, in range hood as described above, emitted gas and air, which contains oily smoke and the like, can be reliably drawn to a certain extent. However, in addition to the above-mentioned problems that, in the case of electromagnetic cooking appliances, insufficient ascending air current in kitchens must be solved, there still reside many other problems to be solved. For example, there reside such problems as “cleaning” as well as “air supply” in recent housings with a high airtightness.
First, in view of “cleaning”, as described above, emitted gas, which is generated in a kitchen, contains “oily smoke”. The oily smoke is generated while cooking flies and stir-fry using oil. The oily smoke accumulates into liquid on walls of the kitchen and the hood resulting in a residue. Particularly, being located close to the frying pan and the like, interior wall 30 at the rear side of a kitchen range as shown in FIG. 1 is an area where “oily residue” readily accumulates. Since the “oily residue” is extremely difficult to remove, every family suffers hard work to remove it.
On the other hand, in view of “air supply”, in a room (kitchen) having a high airtightness, unless special equipment is provided, it is impossible to introduce fresh air used for combustion. When cooking is carried out in a kitchen with a high airtightness, even when a strong range hood is available, fresh combustion air has to be supplied from the inside of the kitchen. Accordingly, emitted gas generated on the kitchen range is spread in the kitchen.
Particularly, in a kitchen with an extremely high airtightness like recent collective housings, due to its high airtightness, it is extremely difficult to supply and evacuate the air by means of air supply fan or natural convection only.
The inventor of the present invention has extensively examined how such range hood can be achieved. That is, in the case where an electromagnetic cooking appliance is used, not only can unsatisfactory ascending air flow be supplemented, but also accumulation of oily residue is on the interior wall is minimized, and still more, even when no special equipment is provided, the air for cooking can be supplied. As a result, the inventor found the fact that, in the emitted gas evacuated from the evacuating duct, not only carbon dioxide gas and vapor but also a part of the air in the room is included, and achieved the present invention.
The present invention has been achieved in view of the above-described problems in the range hoods. Accordingly, an object of the present invention is to provide a range hood that is capable of not only reliably evacuating the air or emitted gas, which contains vapor or the like, to the outside of the house, but also supplementing insufficient ascending air current with air sufficiently to guide the same to the inside of the hood, and preventing oily residue from accumulating on the surface of the interior wall, and further, even in a kitchen with a high airtightness, supplying the air satisfactorily.